Researchers have identified five new genetic mutations associated with Crohn's disease in Jews of Eastern European descent (Ashkenazi Jews) and say their findings may help explain why Crohn's is nearly four times more prevalent in this group than in the general population. Crohn's is an inflammatory bowel disease that causes swelling and irritation in the digestive tract. Symptoms include abdominal pain, diarrhea, rectal bleeding, weight loss, and fever.